<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<style>
    div {
        width: 300px;
        height: 300px;
        background-color: rgb(0, 255, 213);

    }
    .box1 .p1 {
         background-color: red; /*后代选择器 */
    }
    .box1.box2 {
        background-color: rgb(0, 80, 253);
    }
</style>
<body>
    <div class="box1">
        <p class="p1"></p>
    </div>
    <div class="box2"></div>
    <div class="box3"></div>
    <div class="box4">
        <div>
            <p><a href=""></a></p>
        </div>
    </div>
    <div class="box5"></div>
</body>
</html>